1. Field of the Invention
The present invention relates to weapons for destroying deeply buried and hardened targets, and more particularly to plural, tandem warheads sequentially detonated upon reaching the target to increase probability of target destruction.
2. Description of the Related Art
Weapons serve various functions during the defense or attack of a territory. One such objective is the destruction of command and control centers. An increasing number of these potential targets are being buried deep underground and hardened with reinforced concrete overburdens. Until recently, the only capability against such deeply buried and hardened targets has been nuclear warheads. It has now been recognized that such weapons are an unacceptable solution for regional conflicts, and therefore efforts have been pursued to develop penetrating weapons with conventional warheads.
Such efforts have led to a new understanding of penetration physics, including terradynamic stability, as well as novel structural designs to preserve the integrity of the warheads and the fuze mechanism have evolved. U.S. Pat. No. 4,878,432 to Mikhail discloses a novel kinetic energy projectile for penetrating armor. The Mikhail projectile includes multiple, longitudinally stacked, penetrator stages that separate and fly independently of one another during flight, in a rearward to forward sequence. U.S. Pat. No. 4,090,446 to Tomasetti discloses a controlled depth-of-burial penetrator having a front section which, after a predetermined time following impact, separates from the rearward section and scoots off in a direction of about 45 degrees to the direction of motion of the rearward section.
Current work on penetrating weapons capable of destroying buried, hardened targets has focused on increasing penetration depth (see U.S. Statutory Invention Registration No. H867) and developing novel fuze systems to eliminate inaccuracies (see U.S. Pat. No. 4,606,272 to Kerdraon and U.S. Pat. No. 4,878,432 to Mikhail).
Fuzing problems stem from uncertainties relating to the nature of target overburdens. For time delay fuzes, uncertainty of soil composition and the thickness of concrete overburdens can lead to detonations at distances from the target that render the warhead ineffective. More sophisticated fuzes are being developed for measuring accelerations and other phenomena to correct for these uncertainties.
However, target uncertainty also arises due to lack of knowledge of the number of layers of structure to be penetrated, or the material of which the target is constructed, or the soil composition, or the number and frequency of voids. In these circumstances, detonations initiated by even sophisticated fuzes can occur at large distances from the target, thereby rendering the warhead ineffective.
Additionally, counter measures, such as rubble, can be employed in the overburden with introduce randomness to penetrating behavior, further complicating the ability of a sophisticated fuze to detonate in the target.